* Enable -Werror for GCC/Clang builds
Fixes many of the errors this produces, and disables a handful that
didn't have solutions that were obvious (to me).
* Check for `-W*` flags empirically
* Remove cl_APPLE_fp64_basic_ops support
* Undo NAN conversion fix
* Add comments to warning override flags
* Remove unneeded STRINGIFY definition
* Fix tautological compare issue in basic
* Use ABS_ERROR macro in image tests
* Use fabs for ABS_ERROR macro
* Move ABS_ERROR definition to common header
* Allow CL_HALF_FLOAT denorm flushing for write tests (#452)
* On mismatch, add relaxation when denormal half result is expected
* Refactor to use common validation function
* Clean up some diagnostics
* Fix review comments
- use cl_half
- remove extraneous casts
- replace literals with sizeof()
* Document rollover trick for IsHalfSubnormal
* set gDeviceType in testharness.c, also moved gTestRounding to imageHelpers.cpp & .h and removed duplicate code from host_atomics.cpp
* Cleaned up some redundant code
* Reversed the change in testharness.c
* Moved all instances of gDeviceType to imageHelper.cpp
* Missed one instance of gDeviceType
* Removed all instances of extern cl_device_type gDeviceType, except in imageHelpers.h
* Require exact for match normals, instead of arbitrary .005 relative error
* Add relaxation to allow 0 when float denormal is expected
* Refactor to use common validation function
Some of the setup functionality is already there in the test harness, so
use that and remove the duplicated code from within the suite.
Signed-off-by: Radek Szymanski <radek.szymanski@arm.com>
